Tom Grube was one of Siri’s original founders before Apple bought the technology in 2010. He was recently the head of Siri’s Advanced Development group at Apple before stepping down, reports The Information. According to sources close to Grube, he is retiring and plans to pursue other interests including photography and ocean conservation. Apple has also lost its head of search, Vipul Ved Prakash, who joined the company in 2013 after Apple acquired the search engine and analytics company Topsy. Their resignations come a week after Apple announced it had a new AI chief–John Giannandrea, Google’s former artificial intelligence research and search head.